The present invention relates generally to continuous extrusion of metal, and more particularly to a continuous extrusion machine to produce generally continuous lengths of wire strips and other shapes.
In a conventional continuous extrusion process, metal is continuously drawn by friction through a passage to an abutment that obstructs the passage and forces the metal through a die orifice to form a generally continuous extrusion of metal, typically wire. The passage is formed between an annular groove formed in the surface of a rotatable cylindrical die and an arcuate surface of a stationary die. The die orifice is formed in or near the abutment at the end of the passageway. Continuous extrusion machines are typically used for forming copper or aluminum wire (not necessarily round in cross-section).
The present invention relates generally to an improved continuous extrusion machine for extrusion of generally continuous metal shapes from metallic powders, and more particularly for extruding generally continuous shapes from copper powder.
In accordance with a preferred embodiment of the present invention, there is provided a continuous, friction-actuated extrusion apparatus comprised of a cylindrical first member having a circumferential groove formed in its peripheral surface. A stationary second member projects into the groove and defines a passageway between the first member and the second member, the passageway having an entry end and an exit end. Means for rotating the cylindrical first member are provided such that the first member travels in a direction from the entry end to the exit end of the passageway. A metal feeding device feeds metal into the passageway at the entry end. An abutment member extending across the passageway at the exit end thereof forces the metal powder through at least one die orifice located at the exit end of the passageway. At least one restriction member is located in the passageway between the orifice and the entry end, the restriction member constricting the passage for a portion thereof.
In accordance with another aspect of the present invention there is provided a continuous friction-actuated extrusion apparatus, comprised of a passageway extending from an entry end to an exit end between an arcuate first member and a second member. The second member is in the form of a wheel having circumferential groove formed in its peripheral surface into which groove the first member projects. Means are provided for rotating the wheel in such a direction that those surfaces of the passageway constituted by the groove travel from the entry end towards the exit end. Metal feed means for feeding metal into the passageway are provided at the entry end. At least one die orifice is located in or adjacent to an abutment member extending across the passageway at the exit end thereof for extrusion of material from the passageway.
At least one restriction is formed in the passageway between the die orifice and the entry end of the passageway. The restriction reduces the average cross-sectional area of the passageway by at least 40%.
It is an object of the present invention to provide a continuous extrusion machine for continuous, friction actuated extrusion of metal from metal powders.
Another object of the present invention is to provide a machine as described above for extrusion of copper wire from copper powder.
Another object of the present invention is to provide a machine as described above that reduces internal stresses within the formed wire.
A still further object of the present invention is to provide a machine as described above that provides a pre-extrusion process prior to extrusion at the forming die.
These and other objects and advantages will become apparent from the following description of a preferred embodiment of the present invention, taken together with the accompanying drawings.